Gambling for fun wouldn't mean you lose more often in most cases as most games aren't especially based off of skill but blind luck. Fun to me means you aren't chasing the money or feeling you have to win, you play for some entertainment or distraction and likely move on when its not fun.
The premise seems to suggest its still all about the money and the lack of dedication to the task is dangerous somehow. Fun focused playing is opposite to the idea of I will get rich, there is more freedom accepting its just a game; closer to the truth so more likely to win is ironic but feasible imo.
It has to be this way so as not to expect too much when you might be disappointed The casino can disappoint us if we expect too much from it it's not something to ever be overconfident about That's why, as you say, it's better to have a lot of fun and not chase losses That's what makes us free in a casino and prevents us from being tied to expected good results because of strong disappointments.